Abstract
Purpose :
To analyse the foveal avascular zone (FAZ) and the retinal microcirculation in healthy controls using enface optical coherence tomography angiography (OCT-A) with two different devices, the AngioPlex OCT Angiography (prototype Zeiss Meditec) and AngioVue – RTVue XR Avanti (Optovue).
Methods :
Thirty-two eyes from 17 healthy controls performed OCT-A, 3x3mm scan, in the two different devices (AngioPlex and AngioVue), and 6 subjects (12 eyes) repeated scans on a different date for repeatability analysis. Acquisition parameters such as examination time and success rate were registered for systems comparison. The superficial retinal vascular layer (SRL) was depicted as an enface image. Analysis of the SRL was performed by two independent graders and agreement analysis was performed. Descriptive statistics were calculated for FAZ area, perimeter and feret. Vascular density was evaluated in the AngioPlex OCT-A exams using area and length density metrics.
Results :
The mean age of this healthy population was 50±14 years (range 27-73) with 71% being females. The FAZ outline was well-defined and not disrupted but the FAZ measurements showed a wide distribution range. FAZ area in the SRL ranged from 0.07-0.57mm2 in AngioPlex and 0.06-0.55mm2 in AngioVue. Repeatability was good in both systems (ICC: 0.991 for AngioPlex and 0.989 for AngioVue). Acquisition time was longer in the AngioVue vs. AngioPlex (22.4±19.8s vs. 13.0±5.1s) with longer processing time as well as higher number of re-scans needed (24% vs. 12%). Agreement between the two graders was good (ICC: 0.993). Vascular density in the SRL measured in AngioPlex OCT-A exams in the central 3mm showed mean values of area density of 0.46±0.02 and length density of 0.093±0.005. There is a moderate negative correlation between area and length density values with age (-0.405 and -0.475, respectively; p<0.05) and also with FAZ area (-0.555 and -0.559, respectively; p<0.05).
Conclusions :
OCT-A provides detailed information of the parafoveal macular microvasculature. The superficial retinal capillary net identifies well the FAZ size, its outline and the vascular density in the parafoveal ring (central 3mm) with good reproducibility thus allowing reliable identification of alterations of the superficial capillary net in retinal vascular disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.